environ.c

gcc-fortran,linux使用fortran的编译软件。很好用的。

/* Copyright (C) 2002,2003,2005 Free Software Foundation, Inc.
   Contributed by Andy Vaught

This file is part of the GNU Fortran 95 runtime library (libgfortran).

Libgfortran is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file into combinations with other programs,
and to distribute those combinations without any restriction coming
from the use of this file.  (The General Public License restrictions
do apply in other respects; for example, they cover modification of
the file, and distribution when not linked into a combine
executable.)

Libgfortran is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with libgfortran; see the file COPYING.  If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

#include "config.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>

#include "libgfortran.h"
#include "../io/io.h"


/* Environment scanner.  Examine the environment for controlling minor
 * aspects of the program's execution.  Our philosophy here that the
 * environment should not prevent the program from running, so an
 * environment variable with a messed-up value will be interpreted in
 * the default way.
 *
 * Most of the environment is checked early in the startup sequence,
 * but other variables are checked during execution of the user's
 * program. */

options_t options;


typedef struct variable
{
  const char *name;
  int value, *var;
  void (*init) (struct variable *);
  void (*show) (struct variable *);
  const char *desc;
  int bad;
}
variable;

static void init_unformatted (variable *);

/* print_spaces()-- Print a particular number of spaces.  */

static void
print_spaces (int n)
{
  char buffer[80];
  int i;

  if (n <= 0)
    return;

  for (i = 0; i < n; i++)
    buffer[i] = ' ';

  buffer[i] = '\0';

  st_printf (buffer);
}


/* var_source()-- Return a string that describes where the value of a
 * variable comes from */

static const char *
var_source (variable * v)
{
  if (getenv (v->name) == NULL)
    return "Default";

  if (v->bad)
    return "Bad    ";

  return "Set    ";
}


/* init_integer()-- Initialize an integer environment variable.  */

static void
init_integer (variable * v)
{
  char *p, *q;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  for (q = p; *q; q++)
    if (!isdigit (*q) && (p != q || *q != '-'))
      {
	v->bad = 1;
	goto set_default;
      }

  *v->var = atoi (p);
  return;

 set_default:
  *v->var = v->value;
  return;
}


/* init_unsigned_integer()-- Initialize an integer environment variable
   which has to be positive.  */

static void
init_unsigned_integer (variable * v)
{
  char *p, *q;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  for (q = p; *q; q++)
    if (!isdigit (*q))
      {
	v->bad = 1;
	goto set_default;
      }

  *v->var = atoi (p);
  return;

 set_default:
  *v->var = v->value;
  return;
}


/* show_integer()-- Show an integer environment variable */

static void
show_integer (variable * v)
{
  st_printf ("%s  %d\n", var_source (v), *v->var);
}


/* init_boolean()-- Initialize a boolean environment variable.  We
 * only look at the first letter of the variable. */

static void
init_boolean (variable * v)
{
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  if (*p == '1' || *p == 'Y' || *p == 'y')
    {
      *v->var = 1;
      return;
    }

  if (*p == '0' || *p == 'N' || *p == 'n')
    {
      *v->var = 0;
      return;
    }

  v->bad = 1;

set_default:
  *v->var = v->value;
  return;
}


/* show_boolean()-- Show a boolean environment variable */

static void
show_boolean (variable * v)
{
  st_printf ("%s  %s\n", var_source (v), *v->var ? "Yes" : "No");
}


/* init_mem()-- Initialize environment variables that have to do with
 * how memory from an ALLOCATE statement is filled.  A single flag
 * enables filling and a second variable gives the value that is used
 * to initialize the memory. */

static void
init_mem (variable * v)
{
  int offset, n;
  char *p;

  p = getenv (v->name);

  options.allocate_init_flag = 0;	/* The default */

  if (p == NULL)
    return;

  if (strcasecmp (p, "NONE") == 0)
    return;

  /* IEEE-754 Quiet Not-a-Number that will work for single and double
   * precision.  Look for the 'f95' mantissa in debug dumps. */

  if (strcasecmp (p, "NaN") == 0)
    {
      options.allocate_init_flag = 1;
      options.allocate_init_value = 0xfff80f95;
      return;
    }

  /* Interpret the string as a hexadecimal constant */

  n = 0;
  while (*p)
    {
      if (!isxdigit (*p))
	{
	  v->bad = 1;
	  return;
	}

      offset = '0';
      if (islower (*p))
	offset = 'a';
      if (isupper (*p))
	offset = 'A';

      n = (n << 4) | (*p++ - offset);
    }

  options.allocate_init_flag = 1;
  options.allocate_init_value = n;
}


static void
show_mem (variable * v)
{
  char *p;

  p = getenv (v->name);

  st_printf ("%s  ", var_source (v));

  if (options.allocate_init_flag)
    st_printf ("0x%x", options.allocate_init_value);

  st_printf ("\n");
}


static void
init_sep (variable * v)
{
  int seen_comma;
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  v->bad = 1;
  options.separator = p;
  options.separator_len = strlen (p);

  /* Make sure the separator is valid */

  if (options.separator_len == 0)
    goto set_default;
  seen_comma = 0;

  while (*p)
    {
      if (*p == ',')
	{
	  if (seen_comma)
	    goto set_default;
	  seen_comma = 1;
	  p++;
	  continue;
	}

      if (*p++ != ' ')
	goto set_default;
    }

  v->bad = 0;
  return;

set_default:
  options.separator = " ";
  options.separator_len = 1;
}


static void
show_sep (variable * v)
{
  st_printf ("%s  \"%s\"\n", var_source (v), options.separator);
}


static void
init_string (variable * v __attribute__ ((unused)))
{
}

static void
show_string (variable * v)
{
  const char *p;

  p = getenv (v->name);
  if (p == NULL)
    p = "";

  st_printf ("%s  \"%s\"\n", var_source (v), p);
}


/* Structure for associating names and values.  */

typedef struct
{
  const char *name;
  int value;
}
choice;


enum
{ FP_ROUND_NEAREST, FP_ROUND_UP, FP_ROUND_DOWN, FP_ROUND_ZERO };

static const choice rounding[] = {
  {"NEAREST", FP_ROUND_NEAREST},
  {"UP", FP_ROUND_UP},
  {"DOWN", FP_ROUND_DOWN},
  {"ZERO", FP_ROUND_ZERO},
  {NULL, 0}
};

static const choice precision[] =
{
  { "24", 1},
  { "53", 2},
  { "64", 0},
  { NULL, 0}
};

static const choice signal_choices[] =
{
  { "IGNORE", 1},
  { "ABORT", 0},
  { NULL, 0}
};


static void
init_choice (variable * v, const choice * c)
{
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  for (; c->name; c++)
    if (strcasecmp (c->name, p) == 0)
      break;

  if (c->name == NULL)
    {
      v->bad = 1;
      goto set_default;
    }

  *v->var = c->value;
  return;

 set_default:
  *v->var = v->value;
}


static void
show_choice (variable * v, const choice * c)
{
  st_printf ("%s  ", var_source (v));

  for (; c->name; c++)
    if (c->value == *v->var)
      break;

  if (c->name)
    st_printf ("%s\n", c->name);
  else
    st_printf ("(Unknown)\n");
}


static void
init_round (variable * v)
{
  init_choice (v, rounding);
}

static void
show_round (variable * v)
{
  show_choice (v, rounding);
}

static void
init_precision (variable * v)
{
  init_choice (v, precision);
}

static void
show_precision (variable * v)
{
  show_choice (v, precision);
}

static void
init_signal (variable * v)
{
  init_choice (v, signal_choices);
}

static void
show_signal (variable * v)
{
  show_choice (v, signal_choices);
}


static variable variable_table[] = {
  {"GFORTRAN_STDIN_UNIT", 5, &options.stdin_unit, init_integer, show_integer,
   "Unit number that will be preconnected to standard input\n"
   "(No preconnection if negative)", 0},

  {"GFORTRAN_STDOUT_UNIT", 6, &options.stdout_unit, init_integer,
   show_integer,
   "Unit number that will be preconnected to standard output\n"
   "(No preconnection if negative)", 0},

  {"GFORTRAN_STDERR_UNIT", 0, &options.stderr_unit, init_integer,
   show_integer,
   "Unit number that will be preconnected to standard error\n"
   "(No preconnection if negative)", 0},

  {"GFORTRAN_USE_STDERR", 1, &options.use_stderr, init_boolean,
   show_boolean,
   "Sends library output to standard error instead of standard output.", 0},

  {"GFORTRAN_TMPDIR", 0, NULL, init_string, show_string,
   "Directory for scratch files.  Overrides the TMP environment variable\n"
   "If TMP is not set " DEFAULT_TEMPDIR " is used.", 0},

  {"GFORTRAN_UNBUFFERED_ALL", 0, &options.all_unbuffered, init_boolean,
   show_boolean,
   "If TRUE, all output is unbuffered.  This will slow down large writes "
   "but can be\nuseful for forcing data to be displayed immediately.", 0},

  {"GFORTRAN_SHOW_LOCUS", 1, &options.locus, init_boolean, show_boolean,
   "If TRUE, print filename and line number where runtime errors happen.", 0},

  {"GFORTRAN_OPTIONAL_PLUS", 0, &options.optional_plus, init_boolean, show_boolean,
   "Print optional plus signs in numbers where permitted.  Default FALSE.", 0},

  {"GFORTRAN_DEFAULT_RECL", DEFAULT_RECL, &options.default_recl,
   init_unsigned_integer, show_integer,
   "Default maximum record length for sequential files.  Most useful for\n"
   "adjusting line length of preconnected units.  Default "
   stringize (DEFAULT_RECL), 0},

  {"GFORTRAN_LIST_SEPARATOR", 0, NULL, init_sep, show_sep,
   "Separatator to use when writing list output.  May contain any number of "
   "spaces\nand at most one comma.  Default is a single space.", 0},

  /* Memory related controls */

  {"GFORTRAN_MEM_INIT", 0, NULL, init_mem, show_mem,
   "How to initialize allocated memory.  Default value is NONE for no "
   "initialization\n(faster), NAN for a Not-a-Number with the mantissa "
   "0x40f95 or a custom\nhexadecimal value", 0},

  {"GFORTRAN_MEM_CHECK", 0, &options.mem_check, init_boolean, show_boolean,
   "Whether memory still allocated will be reported when the program ends.",
   0},

  /* Signal handling (Unix).  */

  {"GFORTRAN_SIGHUP", 0, &options.sighup, init_signal, show_signal,
   "Whether the program will IGNORE or ABORT on SIGHUP.", 0},

  {"GFORTRAN_SIGINT", 0, &options.sigint, init_signal, show_signal,
   "Whether the program will IGNORE or ABORT on SIGINT.", 0},

  /* Floating point control */

  {"GFORTRAN_FPU_ROUND", 0, &options.fpu_round, init_round, show_round,
   "Set floating point rounding.  Values are NEAREST, UP, DOWN, ZERO.", 0},